Fatal G2 error

Here's the error from G2: Error (ERROR_PERMISSION_DENIED) : Invalid return URL! The requested URL http://piksel.no/wpg2-2/?g2_controller=cart.AddToCart&g2_itemId=40458&g2_return=%2Fwpg2%3Fg2_itemId%3D40458%26g2_wpg2_returnurl%3Dhttp%253A%252F%252Fwww.piksel.no%26g2_wpg2_returnname%3DPIKSEL&g2_returnName=photo tried to insert a redirection to /wpg2?g2_itemId=40458&amp;g2_wpg2_returnurl=http%3A%2F%2Fwww.piksel.no&amp;g2_wpg2_returnname=PIKSEL which is not a part of this Gallery.

in modules/core/classes/GalleryUrlGenerator.class at line 882 (GalleryCoreApi::error)

in init.inc at line 147 (GalleryUrlGenerator::initNavigation)

in modules/core/classes/GalleryEmbed.class at line 129

in /var/www/wordpress/wp-content/plugins/wpg2/wpg2embed.inc at line 47 (GalleryEmbed::init)

in /var/www/wordpress/wp-content/plugins/wpg2/wpg2embed.inc at line 95

in /var/www/wordpress/wp-content/plugins/wpg2/wpg2template.inc at line 46